The theory of and experimentation into respiratory gas exchange--Carl Ludwig and his school

Abstract

Investigations of respiratory functions progressed considerably in the middle of the 19th century. Motive forces for this were the improvement of basic medical sciences due to the progress in science politics, the evolution of exact measuring methods owing to the improvement of natural sciences and the origin of the ideology of antivitalism and organic physics, revealed by the striving of their leading scientists including Carl Ludwig. Formerly, exchange of O2 and CO2 was related merely to the lungs without exact knowledge of data or mechanisms. Ludwig and his pupils improved the analytical methods of G. Magnus and L. Meyer and applied various experimental conditions thus obtaining data allowing the interpretation of the respiratory gas exchange in the organism according to physical laws. It was found that respiratory gases are transported in a chemically bound state; that the binding mechanisms for O2 and CO2 interact; that body tissues extract O2 and release CO2 depending on metabolism, and that partial pressures justify purely physical theories of the gas exchange. These results enabled the investigation of the transporting substance, haemoglobin, by F. Hoppe-Seyler and of the binding and dissociation dynamics by C. Bohr, J.S. Haldane and A. and M. Krogh. Thus Ludwig bridged the gap from qualitative gas analysis to quantitative research into the kinetics of gas binding.